fix undefined variable

which was introduced by the following change:
https://gerrit.mcp.mirantis.net/5865

Related bug: https://mirantis.jira.com/browse/PROD-12259

Change-Id: I88e6ce6cb9debe5769880b104066698b706d7fbf
diff --git a/docker/swarm/stack/elasticsearch.yml b/docker/swarm/stack/elasticsearch.yml
index 1a2cd51..9993ead 100644
--- a/docker/swarm/stack/elasticsearch.yml
+++ b/docker/swarm/stack/elasticsearch.yml
@@ -16,7 +16,7 @@
             ES_JAVA_OPTS: '-Des.enforce.bootstrap.checks=true'
           service:
             cluster:
-              image: ${_param:docker_image_oss_elasticsearch}
+              image: ${_param:docker_image_elasticsearch}
               deploy:
                 replicas: ${_param:elasticsearch_replicas}
                 restart_policy:
@@ -24,4 +24,4 @@
               ports:
                 - ${_param:haproxy_elasticsearch_exposed_port}:${_param:haproxy_elasticsearch_bind_port}
               volumes:
-                - /srv/volumes/elasticsearch:/usr/share/elasticsearch/data
\ No newline at end of file
+                - /srv/volumes/elasticsearch:/usr/share/elasticsearch/data